Aeronautical propeller



Fel). 239 1932. G, B- JACKSON 1,846,337

AERONAUTICAL PROPELLER Filed March 2, 192B 4 Sheets-Sheet 1 Feb G. B. JACKSON 1,846,337

AERONAUTICAL PROPELLER l Filed March 2. 1928 4 Sheets-Sheet 2 f j q@ --Zfwygfwy G. B. JACKSON AERONAUTICAL PROPELLER Feb. 23, 1932.

Filed uarch 2. 1928 i12-Mu! m 4 Sheets-Sheet 3 Feb. .23, 1932. s. B. JAcKsoN 1,846,337

AERONAUTICALJ PROPELLER Filed March 2, 1928 4 Sheets-Sheet 4 fatented twielb. 2W, l of...

PATENT OFFICE GEORGE B. JACKSON', 0F THREE RIVERS, MICHIGAN l AERONAUTICAL PROPELLER Application filed March 2,

rllhis invention relates to improvements to an aeronautical motor of the internal combustion type, and it is concerned more particularly with means by which the products of combustion are educted through the blades of an associated propeller, so as to promote the efliciency of the engine and propeller and also reduce the noise thereof. In the accomplishment of this purpose, the engine exhaust is conducted into a revolving hub which car-- ries the propeller blades through which the exhaust is then passed for discharge at points adjacent the tips and trailing edges thereof. The exhaust gases so discharged from the blades will enter spaces wherein is a partial vacuum resulting from rotation of the propeller blades, thus increasing the efficiency of the propeller and reducingr the noise incident to rotation thereof. It is possible to so design the propeller openings in relation to the speed of engine operation and travel of the aeronautical apparatus, that the vacuum effeet will travel back into the engine so as to permit a change in the timing of the valves thereof, and renderA lpossible the use of a lower' grade of fuel, such as kerosene, furnace oil, or distillate.

An exempliiication of my .invention is set forth in the accompanying drawings whereini Figure l is a front elevation of an aeronautical propeller and motor with which it is associated; j,

Fig. 2 is a plan view thereof, the front end of the motor alone being shown;

F ig. 3 is 'an enlarged detail in vertical section taken on line 3-3 of Fig. 1, and shows the propeller advanced about 90 Figs. 4 and 5 are similar views taken, respectively, on line 4.-21: and 3f-5 of Fig. 3;

Fig. 6 is a detail in section taken on line 6 6 of Fig. l;

Fig. 7 is a detail in section taken on line Ji--Tof F ig. 4;

Fig. 8 is a front elevation of the receivingchamber; and

Figs. 9 and 10 are sectional details taken. respectively, on lines 9 9 and lll-l0 of Fig. 3.

ln the present 1'nvention I aim to take ad- 1928. Serial No. 258,451.

vantage of certain conditions which are present in the operation of an aeronautical motor. Rotation of the propeller creates an air4 dis turbance resulting in the development of a partial vacuum adjacent the tip and the trailing edge of its blades. The rush of air into this void is in large part responsible for the noise attending operation of an aeronautical propeller. It is possible by the means herein disclosed to utilize the products of combus tion from the aeronautical motor to mulile this noise. Such an end is achieved by educting the exhaust gases through the propeller blades for discharge at points adjacent such maximum air disturbance, viz., adjacent the tips and also the trailing edges thereof. By so doing, the space into which the air would normally rush becomes flled,fat least in part, bythe spent gases so as to reduce the noise attendantuponthe operation of the propeller blades, and in addition the minus pressure present at such points of discharge tends to draw the spent gases from the explosion chambers of the engine through the exhaust manifolds thereof. These advantages are followed by numeroiils others affecting the operation of the motor, several of which will be more fully touched upon hereinafter.

By way of exemplification, the drawings herein illustrate a. conventional V-type of aeronautical motor A having each block of cylinders equipped with an exhaust mani fold 1l to the forward end of which is connected a pipe 12. These two pipes which lead from opposite engine sides are joined to a hollow member B forming a receiving chamber for the products of combustion. This member is located adjacent the front end of the forward motor bearing C, and may be provided, as shown, with cooling hns 14 projecting outwardly therefrom. This ree ceiving chamber may have a floating mounting with no direct connection to the engine, but only to the exhaust pipes V12 which lead therefrom. For this purpose, I utilize studs l5 which project from the forward end of the front bearing C, these pins being adapted to enter into pockets 16 which are provided upon the rear face of the member B. With any desired number of such studs are associated compression springs 17 interposed between the front engine bearing and the rear face of the receiving chamber, the purpose being to exert a forward pressure on this member at points which are preferably equidistant from each other and from the axis of the engine shaft.

As indicated clearly in Fig. 3, the shaft 20 of the engine may be tapered at 21 near its forward end in accordance with usual practice. ,Mounted upon the shaft end is a hub 22 having a semi-spherical forward wall 23. Extending radially and oppositely from this semi-spherical wall are tubular walls 24 defining passages which communicate with an annular chamber 25 in the hub. The rear side of this annular chamber is defined by a radial wall 26 in which are provided a plurality of ports 27 separated by relatively narrow webs, all equidistant from the axis of the shaft 20. The radial surfaces 28 delining these ports are slanted'in parallelism, as indicated best in Figs. 4. and 7, the pui'- pose being to deflect the course of gases passing therethrough in. the direction of hub rotation, and thereby reduce resistance to the ,ow thereof. These ports open upon the annular receiving chamber B so as to receive therefrom the spent gases which are educted through the exhaustpipes 12. The hub 22 -is splined at 30 to this propeller shaft, so

as to rotatetherewith; the receiving chamber on the other hand remains motionless, consequently I provide for a tight joint between these .relatively moving arts.

ing chamber is formed with annular pockets in which may be received packing rings 31, preferably one inside of the circle of ports 27, and the other to the outside thereof. Due to the pressure exerted by the springs 17,

the receiving chamber is maintained in closeA contact with the hub so -as to have a leakproof connection therewith.

At the front end of the propeller shaft which is. reduced and threaded in the usual .-mannei,I I have-mounted avnut132 together A with a lock nut 33 by which the hub isfsecure'd removabl in place. The opposite ends of'its radial tu ular portions 24 are flanged outwardly at 35. Resting against each of the flanges so provided is the ase flange 36 .of a hollow blade forming part of the aeronautical propeller, and by means of bolts 37 each blade may be demountably secured to the hub. `As shown best in Fi 3, the inner end of each blade is provide with a tubular extension adapted to fit and-extend within the tubular portions of the hub, thereby adding to the stren The lades which may be of conventional form, as represented in Figs. 1 and 2, are

hollow so as to provide passages clear through to the tip ends. Openings 38 through blade are provided adjacent their tips and Forthis purpase,l the forward face o -the receiv.

h and stability of the blade mountings.

scribed -and discharged through the 'blade' openings into the atmosphere. This pulling force is supplemented by a centrifugal force created by rotation of thepropeller. In addition the constant motion of the propeller tends to cool the blades so as to reduce further the temperature of the exhaust gases which are already cooled to a considerable extent during their travel to this point. These several factors all contribute to an'eduction of the gases with less resistance than formerly. The resulting discharge of the exhaust gases into the partial void adjacent the trailing edges and tips of the blades reduces to a marked degree the explosion noises of the engine.

I claim:

1. In combination, an aeronautical internal combustion engine exhaust having a propeller connected for rotation therewith, the propeller comprising a hollow hub, mounted on the engine shaft and hollow blades forming a passage communicating with the hub chamber, a member forming a receiving chamber in communication lwith the propeller hub, a-loating mountingO for the receiving chamber, and means for educting products of combustion from the engine into the receiving chamber and thence'into the hub and through the propeller blades for discharge into the atmosphere.

2. In combination with an aeronautical internal combustion engine exhaust, a hollow member forming a receiving chamber, a floating mounting for said member co-axial with the engine shaft-Land adjacent one end bear- 3. Iii combination, an aeronautical internal combustion `engine exhaust havin a propeller connected for rotation therewith, the

propeller being provided with a chambered hub and hollow blades extended radially therefrom, a hollow member Jforming a receiving chamber adiacent the hub and 1n 5 communication with the interior thereof, a stationary floating mounting includin stu carried by the engine frame and slida ly engaging openings in the hollow member, means forming a seal between said member l0 and the propellerhub, yieldable means for maintaining the member in close Contact with the hub, and means for conducting products of combustion Jr'rom the engine into the receiving chamber Jfrom whence the gases are educted through the propeller blades for discharge into the atmosphere.

Ll. In combination, an aeronautical internal combustion engine exhaust having a propeller connected for rotation therewith, a propeller comprising a chambered hu mounted on the engine shaft and provided with a lateral wall wherein are ports equidistant Jfrom the hub axis, hollow blades carried by the hub and provided with openings through the walls thereof, a hollow member forming a receiving cham r positione adjacent the lateral wall of the hub, the receiving chamber having an opening in one wall thereof which Jfaces the circle of ports in the radial wall of the hub, means providing a seal between said member an hub, a stationary mounting including studs carried by the engine frame and slidably engaging openings in the hollow member, and spring means 315 for yieldingly maintaining the same closely' against the hub, and means Jrior conducting roducts of combustion from the engine into the receiving chamber Jror eduction through the propeller into the atmosphere. 40 5. ln combination, an aeronautical internal combustion engine exhaust having a propeller connected for rotation therewith, the propeller comprising a hollow hub and hollow blades in mutual communication, there being openings through the walls o the` blade, the hub being rovided with a lateral wall having ports wit opposite edges slanted in the direction of propeller rotation, a hollow member having a stationary mountin 53 adj acent the hub and in contact therewith an the interior of the propeller, said mounting including studs carried by the engine rame 55 and slidably engagin openings in the hollow member, and means or conducting products of combustion from the engine through said member and into the hu for discharge through the propeller. blades into the atmosphere.

GEORGE B. JACKSON. 

